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st: RE: First visit to clinic
From
"Martin Weiss" <[email protected]>
To
<[email protected]>
Subject
st: RE: First visit to clinic
Date
Mon, 20 Sep 2010 15:29:47 +0200
<>
*************
bys id (date):
*************
HTH
Martin
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Paul O'Brien
Sent: Montag, 20. September 2010 15:25
To: statalist
Subject: st: First visit to clinic
i want to create a new variable with the date of the first visit of each
patient:
id date date_of_first_visit
N-00-3558 07/04/2008 07/04/2008
N-00-3558 09/04/2008 07/04/2008
N-00-3558 14/05/2008 07/04/2008
N-00-3563 05/06/2007
N-00-3563 31/03/2010
N-00-3565 05/06/2007
N-00-3565 13/06/2008
N-00-3565 13/06/2008
N-00-3565 05/05/2009
N-00-3565 04/03/2010
N-00-3583 09/09/2008
N-00-3583 27/05/2009
i know this should be easy by i am having trouble using n_1
i have tried:
.sort date
.by id, sort: gen visit=_n==1
but the latter does not have the date in order, only id.
any help gratefully received.
paul
------------------------------
Dr Paul O'Brien
Raymede Clinic
Westside Contraceptive Services
Central London Community Healthcare
Exmoor St
London
W10 6DZ
UK
+44 (0)20 8962 4450
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